Piss angle is an intense math calculation that dudes use when trying not to get back-sprayed while pissing into a urinal.

Pissing against the back wall of the urinal at a 90 degree angle will cause extreme backspray. Thus, a man must strategically place his piss stream onto the side wall of the urinal, prefferably at less than 20 degrees to prevent getting back-sprayed.

Dude why are your pants all wet?
Dude I was pissing in the urinal, and I forgot to adjust my Piss Angle
Bro, never forget to adjust your Piss Angle